MC33341 Motorola, MC33341 Datasheet - Page 13

• Manufacturer Part Number: MC33341
• Description: POWER SUPPLY BATTERY CHARGER REGULATION CONTROL CIRCUIT
• Manufacturer: Motorola

The above figure shows the MC33341 configured for load low–side current sensing allowing common paths for both power and
ground, between the source and load. The Noninverting input paths, Pins 1 and 4, are used to sense the load induced voltage
drop that appears across resistor R S . The internal voltage and current regulation thresholds are selected by the respective
external connections of Pins 2 and 6. Resistor R3 is required in applications where high peak levels of load current are possible
from the battery or load bypass capacitor. The resistor value should be chosen to limit the negative substratecurrent to less than
20 mA. Excessively large values for R3 will degrade the current sensing accuracy.
MOTOROLA ANALOG IC DEVICE DATA
Source
Source
Return
Isolator
Opto
V reg
+
+
V
1.2 R2
th(V)
R1
R2
R1
)
)
1
1
1.2 V
Figure 19. Load Low–Side Current Sensing with
Internally Fixed Current and Voltage Thresholds
8
1
R
R
R
Differential Amp
Disable Logic
Differential Amp
Inverting Amp
R
R
R
V CC
V CC
0.4 V
7
2
MC33341
I reg
V CC
V CC
+
+
1.2 V
R3
V sen
I sen
V
0.2
R
V th
I th
th(I LS
S
0.2 V
V CC
R
S
)
V
6
I
3
)
V CC
Transconductance
V CC
Comp
0.2 V 0.4 V 1.2 V
Amp
Reference
V CC
V CC
5
4
R2
R3
+
I
pk
R1
R
0.02
S
– 0.6
Load
Load
R S
Battery or
Resistive
Load
13